From the title page:
Tyranny of Dragons Edition: August 1, 2014, to February 28, 2015
From the How to Use This Guide section:
The D&D Adventurers League Player’s Guide is a comprehensive guide to all the rules used for official games. In addition to player-focused rules, it contains important information for Dungeon Masters and organizers. It contains special rules for playing Dungeons & Dragons in the official campaign.